I have been working on learning to tune my drums, and have had the benefit of some great advice from this site. In working on my toms last night I noticed that I had a Remo Unicorn head marked as "batter" on both the batter and reso head of my drum. My tuning efforts have resulted in a very "boomy" ringing tone, with quite a lot of sustain (forgive me if these are not quite the right/best descriptions), is this as a result of not having a proper reso head, is the batter too heavy, or should I continue to work on my tuning? I guess I am not sure if this combination of heads could be giving a bad result? I know these unicorn heads do not seem to get a good review, but are they that bad?

Batter heads and reso heads are the same thing....the only exception is on a snare. Whilst it's more common for the reso head to be the same or thinner than the batter head, there are no rules. So when you see someone say they're using a single ply reso, the reso head will be a run of the mill Ambassador, G1 or the like.....which can also be used on the batter side.

Your stock heads are more than likely the same head for batter and reso.

Most batter heads are 7, 10, 12 mil thick some thicker and reso heads are normally 2 or 3 mil for sensitivity sake. Only your ear can determine what you like. I am currently using an Evans EC2 SST tom head on my picollo snare and it sounds great. Give it a try just tighten it up a bit.

Keep in mind that every drum has certain tuning ranges where it tends to "sing" more. These are pitches where the shell is really resonating. It's like a sweet spot. This is particularly true when the batter and reso heads are tuned to the same pitch. By creating an interval between the two heads, this changes. For example, if you tune the reso to a higher pitch than the batter, you should find that there is less sustain.

Some of us are really chasing that resonant sound, but if you want to control it, then tuning can have a big effect.